If I recall correctly, while coaching my daughter's softball team 25 years ago: I watched an Amish farmer with two 4 horse teams plow a field with a 6 bottom plow. One team down and back, switch them out and the next team took it down and back. Took him 4 innings to plow a 10 acre plot. He was faster than I was at 8 yrs. old on a John Deere B with a single bottom plow.